ICCVAM Recommends Non-animal Endocrine Disruptor Screening

The Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) has recommended a non-animal test method to identify estrogen agonist and antagonist activity. In addition to recommending the test, ICCVAM also found the method to provide a number of benefits over the method currently employed in the United States.

The committee recommended the BG1Luc estrogen receptor (ER) transactivation (TA) test method to identify substances with in vitro estrogen activity. The BG1Luc ER TA test method, also known as the Lumi-Cell ER test method, was developed to identify substances that can induce or inhibit human ER activity in vitro. Xenobiotic Detection Systems Inc. developed the test method with the support of a National Institute of Environmental Health Sciences (NIEHS) Small Business Innovation Research grant and nominated the method to ICCVAM for an interlaboratory validation study.

ICCVAM's Interagency Endocrine Disruptor Working Group (EDWG), composed of scientists from ICCVAM member agencies, worked with the National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) to carry out relevant evaluation activities following completion of the international validation study. A background review document, test method performance standards and ICCVAM test method recommendations were reviewed by an independent international peer review panel. ICCVAM considered the panel report and comments from the public, the EDWG, and the Scientific Advisory Committee on Alternative Toxicological Methods (SACATM) in preparing the final test method recommendations.

ICCVAM recommends that the accuracy and reliability of the BG1Luc ER TA test method support its use as a screening test to identify substances that can induce or inhibit human ER activity in vitro. ICCVAM concludes that the accuracy of this assay is at least equivalent to the only ER TA test method currently in a US regulatory test guideline, the Environmental Protection Agency's "OPPTS 890.1300: Estrogen Receptor Transcriptional Activation (Human Cell Line (HeLa- 9903))."

In addition, the BG1Luc ER TA test method was found to offer several advantages over the existing ER TA method, including validation for use over a wider concentration range of test substances, potential to detect a wider range of ER-active substances, ability to identify both substances that induce and inhibit the estrogen receptor, and availability of the cell line used for the test from more than one source.

The ICCVAM evaluation is detailed in a report "ICCVAM Test Method Evaluation Report: The Lumi-Cell ER (BG1Luc ER TA) Test Method: An In Vitro Assay for Identifying Human Estrogen Receptor Agonist and Antagonist Activity of Chemicals (NIH Publication No. 11-7850)." The report also provides performance standards that can be used to evaluate functionally and mechanistically similar test methods, recommended test method protocols, a final background review document describing the current validation status of this test method and recommendations for future studies.

The ICCVAM report and recommendations have been transmitted to federal agencies for their review and response to ICCVAM in accordance with the provisions of the ICCVAM Authorization Act of 2000, which requires agencies to review the recommendations and respond to ICCVAM within 180 days. The BG1Luc ER TA test method was adapted to a high-throughput format using 1536-well plates by the National Institutes of Health (NIH) Center for Translational Therapeutics (NCTT; formerly the NIH Chemical Genomics Center). Preliminary results are promising, and it is expected that this method will be incorporated into the Tox21 screening paradigm in 2012.

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